The Government Accountability Office, the congressional investigative agency, stands to lose up to $50 million in funding this year that its defenders say would force widespread layoffs and the closure of its regional offices. Current budget proposals also would force the agency to detail the costs and manpower used to publish each of its reports, a task that supportive lawmakers fear could politicize the nonpartisan office.

GAO publishes more than 1,000 reports and audits annually, and agency officials frequently testify before congressional committees to detail their findings. Despite its relatively spot-free reputation and the billions of dollars in potential savings it has identified in recent years, House and Senate appropriators responsible for drafting the legislative branch budget seem determined to force the GAO to reduce, as part of a 5.2 percent drop in all congressional spending.

As Washington seeks ways to cut back, “the buck shrinks here,” said Sen. Ben Nelson (D-Neb.), chairman of the Senate appropriations subcommittee on the legislative branch. He said his proposed cuts “are real and will force Congress and the agencies on Capitol Hill to live with less.”

Sen. Ben Nelson (D-Neb.) (Melina Mara/THE WASHINGTON POST)

Nelson’s proposals are infuriating several of his Senate colleagues, particularly Sen. Tom Coburn (R-Okla.), a frequent critic of government spending who often relies on GAO to help him root out cases of waste, fraud and abuse.

Requiring detailed spending reports would “be an overly burdensome mandate that would further consume GAO’s dwindling resources without providing any obvious cost benefit,” Coburn and four other colleagues wrote last week in a letter sent to Nelson’s subcommittee. No other congressional office — including the Congressional Research Service, which also publishes thousands of reports — is required to provide detailed spending totals, they said.

In a separate plea, Sens. Joseph I. Lieberman (I-Conn.) and Susan Collins (R-Maine) asked Nelson to drop plans for detailed spending reports, arguing that they could result in “a politicization of the GAO report process as members and committees are criticized for spending money on a GAO analysis.” Lieberman and Collins, the chairman and ranking Republican on the Senate Homeland Security and Governmental Affairs Committee, favor requiring GAO to conduct one annual spending analysis of its work.

GAO officials declined to comment on the ongoing budget fight but said the agency is offering buyouts and early retirement offers to long-serving employees; 37 have accepted the offers, a spokesman said. The buyouts and early retirement were first offered before the budget debate began.